Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
NTE2343 NTE Electronics, Inc.	TRANS NPN 120V 12A TO220	605
NTE30 NTE Electronics, Inc.	TRANS PNP 80V 50A TO3	16
NTE14 NTE Electronics, Inc.	TRANS PNP 80V 700MA 3SIP	256
MJE172 NTE Electronics, Inc.	TRANS PNP 80V 3A TO225AA	275
NTE192 NTE Electronics, Inc.	TRANS NPN 50V 500MA TO92HS	826
NTE376 NTE Electronics, Inc.	TRANS NPN 300V 200MA TO220	6249
2N5684 NTE Electronics, Inc.	TRANS PNP 80V 50A TO3	60
2N3704 NTE Electronics, Inc.	T-NPN SI- AMP DRIVER	266
NTE158 NTE Electronics, Inc.	TRANS PNP 32V 1A TO1	195
NTE265 NTE Electronics, Inc.	TRANS NPN 50V 500MA TO202	214
NTE81 NTE Electronics, Inc.	TRANS NPN 30V 500MA TO99	8
NTE2311 NTE Electronics, Inc.	TRANS NPN 450V 15A TO3P	466
2N6497 NTE Electronics, Inc.	TRANS NPN 250V 5A TO220AB	237
NTE271 NTE Electronics, Inc.	TRANS PNP 100V 10A TO3PN	15
NTE323 NTE Electronics, Inc.	TRANS PNP 120V 1A TO39	165
NTE16007 NTE Electronics, Inc.	TRANS NPN 55V 3A TO8	53
2N6730 NTE Electronics, Inc.	TRANS PNP 100V 2A TO237	40
NTE36MP NTE Electronics, Inc.	TRANS NPN 140V 12A TO3P	12
NTE93 NTE Electronics, Inc.	TRANS PNP 200V 15A 3SIP	183
NTE16001 NTE Electronics, Inc.	TRANS NPN 35V 50MA 3SIP	116

Transistors - Bipolar (BJT) - Single

1. Overview

Bipolar Junction Transistors (BJTs) are three-terminal semiconductor devices that use both electron and hole charge carriers. They form the foundation of analog electronics through their ability to amplify signals and control current flow. BJTs remain critical in modern electronics for applications ranging from audio amplifiers to power management circuits, offering superior linearity and robustness in switching operations.

2. Main Types & Functional Classification

Type	Functional Characteristics	Application Examples
NPN Transistor	Majority carriers: electrons. Requires positive base current for conduction.	Low-noise amplifiers, digital logic circuits
PNP Transistor	Majority carriers: holes. Conducts with negative base current.	Power supply circuits, motor controllers
High-Frequency BJT	Optimized for RF/microwave signal amplification (f_T > 100 MHz)	Wireless communication systems, radar
Power BJT	High current/voltage ratings (I_C > 1A, V_CE > 50V)	Switch-mode power supplies, motor drives

3. Structure & Composition

BJTs consist of three doped semiconductor regions forming two p-n junctions:

Emitter: Heavily doped region emitting charge carriers
Base: Thin, lightly doped middle region controlling carrier flow
Collector: Moderately doped region collecting carriers

Manufactured using silicon (common) or germanium (historic) with planar processing technology. The structure forms either NPN (n-type emitter/base/collector) or PNP configuration, with metal contacts for external connections.

4. Key Technical Specifications

Parameter	Description	Importance
Current Gain (h_FE)	Ratio of collector to base current (10-1000)	Determines amplification capability
Transition Frequency (f_T)	Frequency at which current gain drops to 1	Limits high-frequency performance
Max Collector Current (I_Cmax)	Maximum allowable continuous collector current	Defines power handling capability
Breakdown Voltage (V_CEO)	Max voltage between collector and emitter	Prevents device failure under stress
Saturation Voltage (V_CEsat)	Voltage drop in fully conducting state	Affects power efficiency in switching

5. Application Areas

Consumer Electronics: Audio amplifiers, LED drivers
Automotive: Engine control units, electric vehicle inverters
Industrial: PLCs, motor controllers
Telecommunications: RF power amplifiers, fiber optic transceivers
Aerospace: Avionics systems, satellite transponders

6. Leading Manufacturers & Products

Manufacturer	Product Series	Key Specifications	Typical Use
ON Semiconductor	2N3904	hFE: 100-300, fT: 300 MHz	General-purpose switching
Infineon	BC547	VCEO: 50V, ICmax: 100mA	Analog signal amplification
STMicroelectronics	2SD2656	ICmax: 15A, VCEO: 80V	Power inverter applications
Diodes Inc.	BFR93A	fT: 10 GHz, Noise Figure: 2dB	High-frequency front-end amplifiers

7. Selection Guidelines

Determine operating frequency: Select fT > 3 target frequency
Power requirements: Ensure Icmax and VCEO exceed circuit requirements by 20%
Thermal considerations: Calculate power dissipation (P=V_CE I_C)
Package type: TO-92 for low power, TO-220 for high-power applications
Environmental factors: Consider temperature ratings for industrial/military use

8. Industry Trends

Future developments include:

High-frequency BJTs operating beyond 100 GHz for 6G communication
Integrated BJT-MOSFET hybrid devices (BiCMOS) for mixed-signal applications
Wide-bandgap materials (SiC/GaN) for higher power density
Miniaturization through chip-scale packaging
Improved thermal management solutions for automotive applications